This invention relates to apparatus for feeding fibers to a carding machine or the like, and more particularly to a pneumatic device for leveling the upper end of a column of fibers deposited in the fiber feeding chute of such machine.
In most pneumatic fiber supply systems of the type described, it is conventional to divert air-borne fibers from an overhead supply or transport duct downwardly into each of a plurality of vertically disposed fiber feed chutes, the lower ends of which are connected with the inputs of carding machines and the like. If such fibers are allowed to accumulate in the center of each chute and then fall by gravity toward its extremities, obviously the height of the column of fibers will be substantially greater at its center as compared to its extremities, and as a consequence the compaction or density of the column of fibers will be greatest at its center and lesser toward its extremities. This makes it extremely difficult to insure that a uniform supply of fibers will be fed from the lower end of each chute into the associated carding machine.
For this reason it is most desirable that fibers be fed downwardly into an associated feed chute in such manner that the upper end of the column of fibers in the chute has a level or uniform profile. For this purpose efforts have been made to produce apparatus which will cause a stream of fibers emanating from an overhead supply duct to be directed back and forth between opposite sides of a supply chute during the filling thereof. For example, U.S. Pat. Nos. 3,787,093 and 3,865,439 each discloses means for producing the uniform filling of a feed chute of the type described with air-borne fibers. The latter patent, which appears to be more pertinent to this invention, suggests that jets of air be introduced selectively to opposite sides of the transport duct so that a stream of fibers will be directed back and forth transversely of the duct during delivery into the feed chute, thus minimizing the tendency of the fibers to build up or concentrate in the center of the chute. Diverting jets of this type have also been disclosed, although for different purposes, by U.S. Pat. Nos. 4,165,134 and 3,458,237. Similar means for controlling the distribution of an air-borne product is disclosed also in U.S. Pat. No. 3,431,027.
Among the disadvantages of the above-noted prior art systems has been the inaccuracy with which a stream of fibers has been diverted from one side to another of a duct. In other words, it has been discovered that the use of air jets alone for diverting the flow of fibers cannot assure that the fiber distribution in the receiving chute will be uniform or satisfactory at all times. Furthermore, in none of these prior art disclosures is there any suggestion of the desirability of interconnecting the jets which control the diversion of a stream of fibers so that uniform diversion can take place automatically.
Accordingly, it is an object of this invention to provide an improved leveling device which is pneumatically operated, and which is capable of accurately diverting the flow of a stream of fibers back and forth in a predetermined pattern during delivery of the fibers into a feed chute or the like.
Still another object of this invention is to provide an improved leveling device of the type described which is operable automatically and repeatedly to divert the flow of a stream of fibers in different directions in order to achieve a uniform distribution of fibers in the receiving chute of the associated apparatus.
A further object of this invention is to provide improved leveling apparatus of the type described which can be readily adjusted to alter the frequency with which a stream of fibers is diverted back and forth between the sides of a supply duct or chute.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.